Feral pigeons are considered (by those that do not love them) to be a BIG problem, but there aren't that many of them around...in the 70s there were estimated to be only 100,000 breeding pairs in the UK , I suspect the number is far lower now. This compares with the RSPB's estimate of 4,935,000 breeding pairs of blackbirds!

But if you have to deter pigeons from lolling, roosting or feeding in an area for which you are responsible, I can recommend: